Additional research and development activities were also performed for the replacement of warheads to ensure long operation of the first- and second-generation missiles. The missiles were indexed as R-21M (in service since 1981) and R-29DU (in service since 1986). The second generation of the military missile complexes involves a cycle of research and experimental activities on the Arktika theme.

Results of activities on the second-generation sea-based missiles

The missile ammunition load was multiply increased at complete automation of their servicing and combat capabilities.
Instant combat readiness, reduced time of prelaunch preparation, fire rapidity, ripple firing, and any-weather launching were put in reality.

The intercontinental range of firing was implemented at adequate target accuracy since missile, nuclear, electronic, shipbuilding and material technologies were improved, the missile launching weight was increased and the weight of warheads was decreased.

The domestic school of sea-based missile building was founded and headed by Academician V.P.Makeyev.

The second-generation missiles were carried by nuclear submarines of the 667А, 667B, 667BDR projects.